Transcriptional regulation of cortical neuron migration by POU domain factors.

The identification of pathways mediated by the kinase Cdk5 and the ligand reelin has provided a conceptual framework for exploring the molecular mechanisms underlying proper lamination of the developing mammalian cerebral cortex. In this report, we identify a component of the regulation of Cdk5-mediated cortical lamination by genetic analysis of the roles of the class III POU domain transcription factors, Brn-1 and Brn-2, expressed during the development of the forebrain and coexpressed in most layer II-V cortical neurons. Brn-1 and Brn-2 appear to critically control the initiation of radial migration, redundantly regulating the cell-autonomous expression of the p35 and p39 regulatory subunits of Cdk5 in migrating cortical neurons, with Brn-1(-/-)/Brn-2(-/-) mice exhibiting cortical inversion.